Based on my experience using DLink IP cameras, the IR LED would spoilt after 2-3 years of continuous operation, which render the camera useless as it cannot see in the dark anymore.

This is bad.

Or is it normal for IR LED to spoilt after certain years of operation?
I tried buying an external IR Illuminator at shopee (China made) but my 2 years old DCS 936L can’t see shit in the dark.

Appreciate your technical insight in this matter. Thanks.